package com.shigen.demo.atguigu;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.LinkedHashMap;

/**
 *
 *
 * @author shigenfu
 * @date 2022/5/27 9:51 上午
 */public class hashMapDemo {

  public static void main(String[] args) {
    HashMap<String, Object> map = new HashMap<>();

    ArrayList<Object> objects = new ArrayList<>();

    LinkedHashMap<String, Object> linkedHashMap = new LinkedHashMap<>();

    map.put(null, 1);

    System.out.println(map);








  }
}
